Apply custom blendMode to PIXI particle effect

[luludada]

Hi, I am new to Pixi.js and I have been searching and looking for the custom blend mode usage with only WebGL in Pixi.js. I looked through the post(

)

and the github PR (https://github.com/pixijs/pixi.js/pull/4049) to explore the possible to create my custom BlendMode. 

Here are my questions:

1. Does pixi v5 support the custom BlendMode like #4049 mentions, and it seems the version that above post uses is v4.5.3

2. I have no idea how to apply the custom BlendMode to the particle effect with reading the repo (https://github.com/pixijs/pixi-particles). I think I should make some change in ParticleUtils.ts, but I have no clue to begin.

3. I also looked the PR about more BlendMode(https://github.com/pixijs/pixi.js/pull/5391), and does this mean if I want to achieve the custom BlendMode,  it can only happen in canvas2D but not in WebGL?

4. If I can not use the method:

var gl = WebGLRenderingContext;

var blend = new PIXI.BlendMode(gl.ZERO, gl.DST_ALPHA, gl.ONE, gl.ONE_MINUS_DST_ALPHA);

sprite.blendMode = blend;

 then how do I construct the shader like

blendFunc(gl.DST_ALPHA, gl.ONE_MINUS_DST_ALPHA) 

Any advices are appreciated! Thanks in advanced!